LA Const., Article IV, Section 17

When a statewide elected official transmits to the presiding officers of the Senate and House of Representatives a written declaration of his inability to discharge the powers and duties of his office, and until he transmits to them a written declaration to the contrary, the person who would succeed to the office when a vacancy occurs shall assume the powers and duties of the office as acting official. §18. Determination of Inability of Statewide Elected Official