Billionaire to take charge of northern town (9)
I believe the answer is:
gateshead
'northern town' is the definition.
(I've seen this before)
'billionaire to take charge' is the wordplay.
'billionaire' becomes 'Gates' (tech billionaire Bill Gates).
'to take charge' becomes 'head' (I've seen this in another clue).
'gates'+'head'='GATESHEAD'
'of' is the link.
(Other definitions for gateshead that I've seen before include "place on Tyneside" , "Town linked to Newcastle" , "Tyneside town" , "Northern town" .)