Restriction on deduction for long-term specified asset prevents concurrent claims under income-tax deduction provisions and legislation. The amendment prevents duplicate tax relief when cost of a long-term specified asset is accounted for under the capital gains reinvestment clauses: such cost cannot be claimed as a deduction from income-tax under the earlier deduction provision for assessment years ending before the operative date, nor as a deduction under the general income deduction provision for assessment years beginning on or after the operative date.