It is much more intuitive, in my opinion, to work with Cursors (rather than trying to emulate the field calculator in a script) for this type of problem.  This is how you would port the problem over to an [Update Cursor][1]:

    import arcpy
    
    # The input FC
    fc = "C:/W/Sik.gdb/yourFC"
    
    with arcpy.UpdateCursor(fc, ["aspect", "aspect_m60"]) as cursor:
        for row in cursor:
            # row[0] = "aspect"
            # row[1] = "aspect_m60"
            if row[0] < 60:
                row[1] = (row[0] - 60) + 360
            elif row[0] == 60:
                row[1] = row[0] - 60
            else:
                row[1] = row[0] - 60
    
            cursor.updateRow(row)


  [1]: http://resources.arcgis.com/en/help/main/10.2/index.html#//018w00000014000000