Delaware constitution
Article II
Section 7

The Senate at the first annual session of every new General Assembly shall choose one of its members president pro tempore, who shall preside in the absence of the Lieutenant-Governor, or in case the latter shall become Governor or while he or she continues in the exercise of the office of Governor by reason of disability of the Governor. The Senate shall also choose its other officers and in the absence of the Lieutenant-Governor and its president pro tempore may, from time to time, as occasion may require, appoint one of its members to preside. The House of Representatives at such first annual session shall choose one of its members speaker and also choose its other officers, and in the absence of the speaker may from time to time, as occasion may require, appoint one of its members to preside.