(a) The original jurisdiction of the circuit courts over felonies and misdemeanors is, in all things, unchanged; except, that when a prosecution for a misdemeanor has been first commenced and is still pending in a district court or a municipal court, the prosecution in the circuit court shall be abated on plea.
(b) The plea provided for in subsection (a) of this section must state that the prosecution in the district court or the municipal court was commenced without the agency, request, participation, connivance or authority of the defendant and must be sworn to. Each and every averment of the plea may be traversed and denied; and if, on the trial of the issue, it appears that such prosecution was commenced by the agency, request, participation, connivance or authority of the defendant, then the jury must be instructed, if it finds either of these facts to exist, to find the issue in favor of the state, and the case must proceed to trial in the circuit court, as the case may be.