How to show old contract amount received in GSTR 1

My Client doing Government Contracts in PWD He received a Cheque of Rs. 75,68,900/-  on March 2018 The work finsihed on Before GST period in April 2017 itself but he receive the cheque now and in current working period New Work Taken After GST Period and they asked to pay GST 12% on Gross Value now  i want to know whether i want to show this cheque in GSTR - 1 if yes which column i want to show  in exemted or NON GST Supplies - While Filing IT the above mention amount shown in 26AS along with TDS.