(a) Except as provided by Subsection (b), in a proceeding in connection with workers' compensation benefits provided by a political subdivision as a self-insurer, the political subdivision may be represented by:
(1) the political subdivision's attorney or that attorney's assistants; or
(2) outside counsel.
(b) In a proceeding involving workers' compensation for employees of a municipal utility operated by a board of trustees established under Section 1502.070, Government Code, or a similar law, if the board of trustees is a self-insurer, the municipality shall be represented by the regularly employed attorney or outside counsel of the board of trustees.