I dont think standing demand, you were abled to filed your 3B. Re-check. You were required to pay cash through challan and offset your tax liability or through your input tax credit before filing your 3B data.
Yes. I know the demand is as per your record. But, As per GSTR 3B your payable amount is different from your record.... You can adjust your mistakes in GSTR 1 and 2 returns....
But, Advisable for pay your payable portion as per Return Of amount is smaller.... Then you can run your business peacefully..... It is my view only....