One who helps another to a seat (7)
I believe the answer is:
elector
'one who helps' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'another to a seat' is the wordplay.
I cannot quite understand how this works, but
'another' could be 'r' (I've seen this in other clues) and 'r' is located in the answer.
'to' is present in the answer.
The remaining letters 'elec' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for elector that I've seen before include "Germanic prince" , "might he make one cross?" , "One whom may vote" , "Someone with the right to vote" , "one given a choice" .)