Presiding at sitting of the National Assembly and at joint sittings
Section 53(2)(b) · 1999 Constitution (2004 edition)
What Constitution says
(b) in the absence of the persons mentioned in paragraph (a) of this subsection, the Deputy President of the Senate shall preside, and in his absence the Deputy Speaker of the House of Representatives shall preside.
This is the 1999 Constitution as published in 2004. Later amendments aren't included yet, so a section may have changed since.
Original source
Official Gazette · CFRN 1999 official PDF · printed page 44. Original document
Release: draft-c8d50d87fae9. Source scope, review and corrections