If you have a spatial analyst license and the raster the contours came from you can follow the workflow in Colouring areas between (vector) contours? as translated for Esri and performed interactively in ArcMap:

If you have a spatial analyst license and the raster the contours came from you can follow the workflow in Colouring areas between (vector) contours? as translated for Esri and performed interactively in ArcMap:

Alternate (Spatial Analyst) method, much faster

If you have a spatial analyst license and the raster the contours came from you can follow the workflow in Colouring areas between (vector) contours? as translated for Esri and performed interactively in ArcMap:

Use the Zonal Statistics as Table tool to create a table using the polygons as input zones and FID (OBJECTID) as the zone field, I used statistics type "ALL" to avoid confusion later. This gives you a table with the raster statistics (min & max) for each polygon - and it's really fast!

Add fields to the polygons for the minimum and maximum elevation and then join the zonal statistics table (join in ArcMap polygon FID to ZonalTable ObjectID_1 or FID_1 depending on table type, either way it should be the second field in the zonal stats table) to your polygon and use the calculation like this:

MinElev = round( !ZonalStatsObjectID.MIN!,0 )
MaxElev = round( !ZonalStatsObjectID.MAX!,0 )

The name of the zonal statistics table in this example is ZonalStatsObjectID, change to match your table name. Do NOT use int( !ZonalStatsObjectID.MIN!), that's a truncation and will give you the wrong value.

After rounding and copying the values for min and max use field calculator on the table to calculate the nilai field:

def CalcNilai(Min,Max):
    if Min == Max:
        return "%d" % Min
    else:
        return "%d - %d" % (Min,Max)

Which should look like this (I've removed the join for simplicity):

import sys, os, arcpy

InPolygons = sys.argv[1]
NearContour = sys.argv[2]
OutPolygons = sys.argv[3]

ElevationFieldName = "Elevation" # change this to match your field name

InFolder = os.path.dirname(InPolygons) # the folder the input is in
Working = InFolder + "\\Working.gdb"
WorkingContour = Working+"\\Contour"
WorkingPoly = Working+"\\Poly"

arcpy.CreateFileGDB_management(InFolder,"Working.gdb") # create a working space
arcpy.AddMessage("Copy 1")
arcpy.CopyFeatures_management(NearContour,WorkingContour) # need to do this to take charge of names
arcpy.AddMessage("Copy 2")
arcpy.CopyFeatures_management(InPolygons,WorkingPoly) 

# remove 'bad' edges, tagged with elevation = -9999 to show they are a boundary
arcpy.MakeFeatureLayer_management(WorkingContour,"Remove",ElevationFieldName + " = -9999")
arcpy.DeleteFeatures_management("Remove")
arcpy.Delete_management("Remove") # relax, it's just removing the layer, just to keep it clean

# Create a near table
arcpy.AddMessage("Near table")
arcpy.GenerateNearTable_analysis(WorkingPoly,WorkingContour,Working+"\\NearTable","0",closest="ALL")
arcpy.AddField_management(Working+"\\NearTable","Elev","DOUBLE")

try:
    arcpy.AddIndex_management(Working+"\\NearTable","NEAR_FID","NEAR_FID")
except:
    arcpy.AddWarning("Unable to index")

# join and copy elevations
arcpy.AddMessage("Join & calc")
arcpy.MakeTableView_management(Working+"\\NearTable","View")
arcpy.AddJoin_management("View","NEAR_FID",WorkingContour,"OBJECTID")
arcpy.CalculateField_management("View","NearTable.Elev","!Contour."+ElevationFieldName+"!","PYTHON")
arcpy.Delete_management("View") # relax, it's just removing the table view, just to keep it clean

# remove join and summary statistics
arcpy.AddMessage("Make stats")
#arcpy.RemoveJoin_management("View")
arcpy.Statistics_analysis(Working+"\\NearTable",Working+"\\NearStats",[["Elev","MIN"],["Elev","Max"]],"IN_FID")

# copy the min and max to the working contours
arcpy.AddMessage("Copy min/max")
arcpy.AddField_management(WorkingPoly,"MinElev","DOUBLE")
arcpy.AddField_management(WorkingPoly,"MaxElev","DOUBLE")
arcpy.MakeFeatureLayer_management(WorkingPoly,"Layer")
arcpy.AddJoin_management("Layer","OBJECTID",Working+"\\NearStats","IN_FID")
arcpy.CalculateField_management("Layer","Poly.MinElev","!NearStats.Min_Elev!","PYTHON")
arcpy.CalculateField_management("Layer","Poly.MaxElev","!NearStats.Max_Elev!","PYTHON")
arcpy.RemoveJoin_management("Layer")
arcpy.Delete_management("Layer") # relax, it's just removing the layer, just to keep it clean

# check for field
arcpy.AddMessage("Checking for field")
Fields = arcpy.ListFields(WorkingPoly,"nilai")
if not Fields:
    arcpy.AddMessage("-Adding field")
    arcpy.AddField_management(WorkingPoly,"nilai","TEXT",field_length="10")

# format the field with the min and max,
# this could be done with a field calculation
# but in this case I want a special case for isolations
arcpy.AddMessage("Cursoring")
with arcpy.da.UpdateCursor(WorkingPoly,("nilai","MinElev","MaxElev")) as UpCur:
    for Feat in UpCur:
        if (Feat[1]==Feat[2]):
            # values are the same = an isolation
            Feat[0] = str(int(Feat[1]))
        else:
            Feat[0] = "%d - %d" % (Feat[1],Feat[2])
        UpCur.updateRow(Feat)

arcpy.AddMessage("Copy out")
arcpy.CopyFeatures_management(WorkingPoly,OutPolygons) 

import sys, os, arcpy

InPolygons = sys.argv[1]
NearContour = sys.argv[2]
OutPolygons = sys.argv[3]

ElevationFieldName = "Elevation" # change this to match your field name

InFolder = os.path.dirname(InPolygons) # the folder the input is in
Working = InFolder + "\\Working.gdb"
WorkingContour = Working+"\\Contour"
WorkingPoly = Working+"\\Poly"

arcpy.CreateFileGDB_management(InFolder,"Working.gdb") # create a working space
arcpy.AddMessage("Copy 1")
arcpy.CopyFeatures_management(NearContour,WorkingContour) # need to do this to take charge of names
arcpy.AddMessage("Copy 2")
arcpy.CopyFeatures_management(InPolygons,WorkingPoly) 

# remove 'bad' edges, tagged with elevation = -9999 to show they are a boundary
arcpy.MakeFeatureLayer_management(WorkingContour,"Remove",ElevationFieldName + " = -9999")
arcpy.DeleteFeatures_management("Remove")
arcpy.Delete_management("Remove") # relax, it's just removing the layer, just to keep it clean

# Create a near table
arcpy.AddMessage("Near table")
arcpy.GenerateNearTable_analysis(WorkingPoly,WorkingContour,Working+"\\NearTable","0",closest="ALL")
arcpy.AddField_management(Working+"\\NearTable","Elev","DOUBLE")

try:
    arcpy.AddIndex_management(Working+"\\NearTable","NEAR_FID","NEAR_FID")
except:
    arcpy.AddWarning("Unable to index")

# join and copy elevations
arcpy.AddMessage("Join & calc")
arcpy.MakeTableView_management(Working+"\\NearTable","View")
arcpy.AddJoin_management("View","NEAR_FID",WorkingContour,"OBJECTID")
arcpy.CalculateField_management("View","NearTable.Elev","!Contour."+ElevationFieldName+"!","PYTHON")
arcpy.Delete_management("View") # relax, it's just removing the table view, just to keep it clean

# remove join and summary statistics
arcpy.AddMessage("Make stats")
#arcpy.RemoveJoin_management("View")
arcpy.Statistics_analysis(Working+"\\NearTable",Working+"\\NearStats",[["Elev","MIN"],["Elev","Max"]],"IN_FID")

# copy the min and max to the working contours
arcpy.AddMessage("Copy min/max")
arcpy.AddField_management(WorkingPoly,"MinElev","DOUBLE")
arcpy.AddField_management(WorkingPoly,"MaxElev","DOUBLE")
arcpy.MakeFeatureLayer_management(WorkingPoly,"Layer")
arcpy.AddJoin_management("Layer","OBJECTID",Working+"\\NearStats","IN_FID")
arcpy.CalculateField_management("Layer","Poly.MinElev","!NearStats.Min_Elev!","PYTHON")
arcpy.CalculateField_management("Layer","Poly.MaxElev","!NearStats.Max_Elev!","PYTHON")
arcpy.RemoveJoin_management("Layer")
arcpy.Delete_management("Layer") # relax, it's just removing the layer, just to keep it clean

# check for field
arcpy.AddMessage("Checking for field")
Fields = arcpy.ListFields(WorkingPoly,"nilai")
if not Fields:
    arcpy.AddMessage("-Adding field")
    arcpy.AddField_management(WorkingPoly,"nilai","TEXT",field_length="10")

# format the field with the min and max,
# this could be done with a field calculation
# but in this case I want a special case for isolations
arcpy.AddMessage("Cursoring")
with arcpy.da.UpdateCursor(WorkingPoly,("nilai","MinElev","MaxElev")) as UpCur:
    for Feat in UpCur:
        if (Feat[1]==Feat[2]):
            # values are the same = an isolation
            Feat[0] = str(int(Feat[1]))
        else:
            Feat[0] = "%d - %d" % (Feat[1],Feat[2])
        UpCur.updateRow(Feat)

arcpy.AddMessage("Copy out")
arcpy.CopyFeatures_management(WorkingPoly,OutPolygons)