What is Incumbent on?
Incumbent on definition and meaning on Dictionary terms:
holding an indicated position, role, office, etc., currently: the incumbent officers of the club.
obligatory (often followed by on or upon): a duty incumbent upon me.
Archaic. resting, lying, leaning, or pressing on something: incumbent upon the cool grass.
the holder of an office: The incumbent was challenged by a fusion candidate.
British. a person who holds an ecclesiastical benefice.