The bit left, I take over (7)
I believe the answer is:
portion
'the bit' is the definition.
(thesaurus)
'left i take over' is the wordplay.
I cannot quite see how this works, but
'left' could be 'port' (left side of a ship - opposite of starboard) and 'port' is found in the answer.
'i' is present in the answer.
'over' could be 'on' (physically on top of) and 'on' is found in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for portion that I've seen before include "Share, helping" , "Part of a whole" , "Amount of food" , "Serving" , "allotment" .)