Presumptive tax under 44ada

I am a Govt Pensioner . At present working as technical Consultant and receive my professional fees through Invoice under section 194J with 10% deduction of Tax by the employer. My total Receipt including pension is less than 50 lakh per annum . Can i use  Section 44 ADA for calculating my   professional income   and  add my pension to calculate my total Income for tax puposes . Which ITR i should file in such case.

Thanks

Pradeep