Article I, Section 2 of the Constitution says, “The House of Representatives shall be composed of members chosen every second year by the people of the several states, and the electors in each state shall have the qualifications requisite for electors of the most numerous branch of the state legislature.” My position is that since the District of Columbia is not a state, it isn’t to have House members.
Presently, DC and some territories have delegates in the House. They are allowed to vote in committees, which I see as unconstitutional. The politics of the question are highly race-correlated, so although all of the delegates are Democrats, it’s unlikely that Republicans will ever rectify the situation.