District of Columbia National Guard Retention and College Access Act - Authorizes the commanding general of the District of Columbia National Guard to provide financial assistance to members of the District of Columbia National Guard who satisfactorily complete initial active duty service and agree to serve for a period of not less than six years, to assist in them in covering expenses they incur while pursuing their first undergraduate, masters, vocational, or technical degree or certification at an approved institution of higher education. Limits such assistance to up to $400 per credit hour, but not to exceed $5,000 per year.