Legal ownership of bucket: it leaks (5)
I believe the answer is:
title
'legal ownership' is the definition.
(I've seen this before)
'of bucket it leaks' is the wordplay.
'of' indicates the answer is hidden within the clue.
'TITLE' is hidden within 'bucket it leaks'.
(Other definitions for title that I've seen before include "Proprietorship" , "label" , "headline?" , "Handle" , "What could be professor's" .)