Sold Leasehold Garage room-Taxation treatment

Dear Experts,

An assessee had taken a garage room on sub lease for 50 years in 1992,now in 2019,he has entered into sub-lease agreement and transferred the property resulting in Capital Gains .The difference between Consideration received and Stamp duty valuation is huge.Please guide with following queries :                                        1) As per reading of case laws,section 50C is not applicable on sale of leasehold property,kindly guide whether it is true that section 50C is not applicable in leasehold property?                        2) If above answer is yes,then while filing ITR, whether long term capital gain to be shown in Point-B-10 (From sale of assets where B1 to B9 above are not applicable) as in point-B1,it asks for Stamp duty Valuation.

Thanks in Advance