List down the MapLight ID of the representatives in Maine.
representatives refers to type = 'rep'; Maine refers to state = 'ME';
SELECT T1.maplight_id FROM historical AS T1 INNER JOIN `historical-terms` AS T2 ON T1.bioguide_id = T2.bioguide WHERE T2.type = 'rep' AND T2.state = 'ME' GROUP BY T1.maplight_id