Range 12 is the range allotted to you.
The assessment is done by the Assessing officer of Range 12.
Range Nos. are allotted as per profession, government servant, pensioners, address location, etc...
If your PAN card was issued in Mumbai and return filed in Hyderabad, you case for IT refund comes under PAN migration.
The following threads will be of help to you:
Income tax refund - Received by using RTI ! Not received any reply from 2nd PIO