Government leader, getting on a bit, produces wealth (4)
I believe the answer is:
gold
'a bit produces wealth' is the definition.
'gold' can be an answer for 'wealth' (gold can mean wealth or riches). I am not certain of the 'a bit produces' bit.
'government leader getting on' is the wordplay.
'leader' suggests taking the first letters.
'getting on' becomes 'old' ('getting on a bit' means 'old').
The initial letter of 'government' is 'g'.
'g'+'old'='GOLD'
Can you help me to learn more?
(Other definitions for gold that I've seen before include "first gets this?" , "Au - metal" , "gift from a king" , "Mine produces this" , "bull's-eye" .)