Work for the scientists from old, old city (6)
I believe the answer is:
labour
'work' is the definition.
(labour is a kind of work)
'the scientists from old old city' is the wordplay.
'the scientists' becomes 'lab' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'from' says to put letters next to each other.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'old city' becomes 'ur' (ancient city state).
'lab'+'o'+'ur'='LABOUR'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for labour that I've seen before include "What mothers have been through" , "opposition" , "Men are never in this" , "Hard work, party" , "Left - work" .)