The second-in-command has an obligation to carry a record (6)
I believe the answer is:
deputy
'the second-in-command' is the definition.
(I've seen this before)
'an obligation to carry a record' is the wordplay.
'an obligation' becomes 'duty' (synonyms).
'to carry' means one lot of letters goes inside another.
'a record' becomes 'EP' (abbreviation for extended play record).
'duty' enclosing 'ep' is 'DEPUTY'.
'has' is the link.
(Other definitions for deputy that I've seen before include "Stand-in, delegate" , "The next in command, replaces boss when necessary" , "number two" , "Not the principal" , "Subordinate" .)