As per section 45 of Income Tax Act'1961, the profits or gains arising out of transfer of capital asset shall be chargeable to capital in the year in which transfer took place.
Section 45 is reproduced here as fallows:
Any profits or gains arising from the transfer of a capital asset effected in the previous year shall, save as otherwise provided in sections 54, 54B, 54D, 54E, 54EA, 54EB, 54F, 54G and 54H, be chargeable to income-tax under the head "Capital gains", and shall be deemed to be the income of the previous year in which the transfer took place.
In the preset scenario the you have just entered in to agreement transfer yet take place, there fore the said capital gain if any shall be liable income tax in FY 2019-20.
However, you can avail stamp duty value for computation of capital gain as on agreement date if the consideration received mode other than cash, if the total consideration is less the stamp duty value.
Let us know if any clarification/information required.