As amemded by Finance Act 2019-
LTCG on sale of residential house property will be exempt if Capital gains is invested in two residential house
properties in India (“new houses”) .
The amount of capital gain exempt here is limited to Rs 2 crore.
The benefit is available only once in a life time of the tax payer.
Since you have invested in one property only, in my opinion exemption shall be allowed.
Hope it helps.