Leader with due deference to me (10)
I believe the answer is:
pacesetter
'leader' is the definition.
(I have seen 'temporary leader' mean 'pacesetter' so perhaps 'leader' could also mean 'pacesetter')
'with due deference to me' is the wordplay.
'with due deference to' becomes 'pace' (Latin term meaning 'with due respect to').
'me' becomes 'setter' (the person that set this crossword).
'pace'+'setter'='PACESETTER'
(Other definitions for pacesetter that I've seen before include "One who's performance gives the standard for others to reach" , "early leader in race" , "One establishing standard" , "temporary leader" , "Runner" .)