GST TDS and Income Tax TDS are Separate provisions
Question : As a DDO I am deducting TDS while making payment of other bills under Income Tax Act. Then why should I need to deduct TDS again under GST?
Answer: TDS under Income Tax is different from TDS under GST.
There was a provision of TDS under VAT Act also.
TDS under the GST Law is different from the above. Deductions of tax under the GST Laws is required to be made wherever applicable while making payments to the suppliers/ vendors of goods or services or both under GST for taxable supply of goods or services or both.
Comment : Thus TDS is required to be deducted under Income Tax as per Income Tax provisions and under GST Act as per Section 51 of CGST Act 2017
Amount deducted under GST Act (GST TDS ) will be credited to the supplier Electronic Cash Ledger Account (after acceptance by the Supplier on GST Portal) from where he can use to pay his GST liability or can claim refund.
Amount deducted under Income Tax Act (Income Tax TDS) will be available for Credit when the Assessee will file his Income Tax return. This will be adjusted from Income Tax payable by the Assessee or if no income Tax is payable then he can claim refund under Income Tax Act at the time of filing of his income tax return.
Refer
Section 51 of CGST Act 2017 : TDS under GST
Section 194C of Income Tax Act : TDS under Income Tax : Payments to contractors.