GSTR 1

31/01/2019 is correct 

GST portal but wrongly shows 11/01/2019

How to amend Nil or Exempted supplies in GSTR-1

I forgot to mention the Figure while filing it

Please advice.

I am filing GSTR 1 Quarterly so it means that when I filed GSTR 1 for Oct-Dec 18 and forgot to mention the Nil or Exempted figure, now I should mention those figures again in March 19 along with Jan - Mar Figure

Hope I am right?