The role of the conductor? (7,4)

'the' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.

'role of the conductor?' is the wordplay.
I cannot really see how this works, but
'role' could be 'part' (eg a part or role in a film) and 'part' is found within the answer.
'conductor?' could be 'leadin' (lead-in is a kind of conductor) and 'leadin' is located in the answer.
A single letter 'g' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?