(a) Any person summoned to serve as a witness in a criminal case
shall be excused by the judge from attendance at the court by reason of his attendance as a legislator at the General Assembly.
(b) In all criminal cases, it shall be the duty of the presiding judge, on motion of either the state or the defendant, to continue the case when it appears that a material witness is absent from the court by reason of his attendance at the General Assembly.