I have written about area's statesman (5)
I believe the answer is:
iowan
'statesman' is the definition.
(Iowa is a state)
'i have written about area's' is the wordplay.
'have' becomes 'own' ('own' can be a synonym of 'have').
'written about' is an insertion indicator.
'area' becomes 'a' (maths abbreviation).
'own' going around 'a' is 'owan'.
'i'+'owan'='IOWAN'
(Other definitions for iowan that I've seen before include "US resident" , "From a US state, capital Des Moines" , "Someone from the Midwest - a wino? (anag)" , "From Des Moines, say?" , "Statesman" .)