Working in Capitol I could be Congressman (10)
I believe the answer is:
politician
'could be congressman' is the definition.
(I've seen this before)
'working in capitol i' is the wordplay.
'working' is an anagram indicator.
'in'+'capitol'+'i'='incapitoli'
'incapitoli' is an anagram of 'POLITICIAN'.
(Other definitions for politician that I've seen before include "could be Congressman" , "US senator?" , "One in Westminster" , "Eg, an MP" , "Legislator" .)