State tax filing

You will want to go back to the entry section where you first entered the Miscellaneous Income to remove it. 

To do this, open your return in TurboTax Online, select to go to the Wages & Income section of your Federal return.  (Once your return is opened, be sure Federal is selected in left hand column and the Wages & Income tab is selected at the upper left of the screen). 

Then scroll down to Less Common Income and select Revisit for Miscellaneous Income (if that is the section where you entered the amount).  See the sample screenshot.

Then select to Revisit the section where you entered the information and go through the screens, answering them the same way you did before to be brought to the screen where your entry was originally.  On that entry screen, you should be able to remove that entry from the field(s) there.