Invoice Given in Aug 2020 TDS Deducted in Oct 2020

I am doing IOCL Contract Work I Have given invoice to IOCL on Aug 2020 but they release the payment in Oct 2020 and Deduct the 2% GST TDS  in Oct 2020 only i want to know whether i should show the invoice in Aug GSTR 3B or Oct 3B kindly do the needful