Duty of female in charge, leader of expedition (6)
I believe the answer is:
office
'duty' is the definition.
(I know that office is a type of duty)
'of female in charge leader of expedition' is the wordplay.
'female' becomes 'f' (common abbreviation).
'in charge' becomes 'ic' (abbreviation for 'in charge').
'leader of' indicates taking the first letters.
The initial letter of 'expedition' is 'e'.
'of'+'f'+'ic'+'e'='OFFICE'
(Other definitions for office that I've seen before include "Position of authority" , "Job - place of work" , "Position in government?" , "Business room or religious rite" , "Place for administration business" .)