1) Sale of residential plot has been done in April 2017
2) LTCG is exempt for an individual on sale of a residential property, if such gains (not the whole consideration) is utilised to purchase or construct another residential house.in your case since you are selling residential plot after 13 years it would attract LTCG
3) It should be noted that the new house should be purchased within one year before or two years after the date of transfer. In case of construction, the new house should be constructed within three years from the date of transfer.
I 4) n the alternative it is provided that LTCG can be availed in respect of of under construction house if it is completed within period of 3 years from date of transfer of house .