Tex. Const. art. XVI, § 72
(c) For an officer who is a member of the legislature, the member of the legislature shall select a person to serve as the temporary acting representative or senator, subject to approval of the selection by a majority vote of the appropriate house of the legislature. The temporary acting representative or senator must be:
(g) A temporary acting officer appointed under this section shall perform the duties of office for the shorter period of:
(Added Sept. 13, 2003.)