leadership vs ability

leadership and ability both are nouns.

Word	Noun	Adjective	Verb	Adverb
leadership	Yes	No	No	No
ability	Yes	No	No	No

As nouns, ability is a hypernym of leadership; that is, ability is a word with a broader meaning than leadership:

leadership: the ability to lead
ability: possession of the qualities (especially mental qualities) required to do something or get something done

Other hypernyms of leadership include power.

leadership (noun)	ability (noun)
the activity of leading	the quality of being able to perform; a quality that permits or facilitates achievement or accomplishment
the ability to lead	possession of the qualities (especially mental qualities) required to do something or get something done
the body of people who lead a group
the status of a leader