SEC. 601. [D.C. Code 1-206] Notwithstanding any other provision of this Act, the Congress of the United States reserves the right, at any time, to exercise its constitutional authority as legislature for the District, by enacting legislation for the District on any subject, whether within or without the scope of legislative power granted to the Council by this Act, including legislation to amend or repeal any law in force in the District prior to or after enactment of this Act and any act passed by the Council.
Funny how actually reading the act shows Congress can do what it want...
Credit to Hugh