D.C. Code § 49-901
Whenever the National Guard of the District of Columbia shall be ordered to duty in case of riot, tumult, breach of the peace, or whenever called in aid of the civil authorities, all enlisted men who do duty shall be paid at the rate equivalent to 2 times the pay of enlisted men of the regular Army of like grade. Commissioned officers who do duty shall be entitled to and shall receive the same pay and allowances as commissioned officers of like grade of the regular Army. Each mounted officer and enlisted man shall be paid a reasonable per diem compensation for each horse actually furnished and used by him; provided, that when the National Guard of the District of Columbia is called into actual service of the United States the officers and enlisted men shall, during their time of service, be entitled to the same pay and allowances as are or may be provided by law for the regular Army.
D.C. Code § 49-901