Sales of vacant site purchases not shown in i.t.return

Assess sales of vacant site value rs.3,50,000/- Dt: 20-03-2020 f.y.2019-2020. this site purchases value rs.1,70,000/- Dt:20-05-2012 f.y.2012-2013. but Assess mistake site purchases value not mentioned in I t.returns(books not entered)f.y.2012-2013
doubt:
Assess f.y.2019-2020 sales of site Value rs.3,50,000/- show in I.t. return s compulsory
how to adjustment producure of site value in books and I.t. returns.