50A. 5[ Relief from estate duty where gift- tax has been paid. Where tax has been paid under the Gift- tax Act, 1958 , (18 of 1958 ) in respect of a gift of any property and the property is also included in the estate of the donor as property passing under this Act, then, notwithstanding anything contained in this Act, the estate duty payable under this Act shall be reduced by an amount equal to the amount of gift- tax paid in respect of any such property under that Act.]