I once wandered into DC’s hood on a lark with my Dad back in Reagan’s day. Looked like something out of the Third World. Needless to say made our way back without incident to the DC all the tourists frequent. No problems there.
Alexandria, VA next door is lovely. Word of advice: don’t visit there in the middle of summer. Its like a sauna and the heat is debilitating well into the night. Even an air-conditioned hotel room offers scant relief.