An incumbent official is someone who holds an official post at a particular time.
the only candidate who defeated an incumbent senator.
唯一击败了现任参议员的候选人。
If it is incumbent on or upon you to do something, it is your duty or responsibility to do it.
She felt it was incumbent on herself to act immediately.
她感到立即采取行动是她义不容辞的责任。
incumbents
An incumbent is someone who holds an official post at a particular time.
In general, incumbents have a 94 per cent chance of being re-elected.
一般情况下,现任官员有94的几率会再次当选。