To what political party do the politicians graduated from Somerville college, Oxford belong to?
SELECT DISTINCT ?uri WHERE { ?x <http://dbpedia.org/ontology/almaMater> <http://dbpedia.org/resource/Somerville_College,_Oxford> . ?x <http://dbpedia.org/ontology/party> ?uri  . ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/OfficeHolder>}
Somerville_College,_Oxford