Question: When was the last the Dallas Cowboys Helmet won the super bowl?
Answer(s):
answer: Super Bowl XXX

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ?c)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
?c ns:common.topic.image ns:m.02kzx1t . 
?c ns:sports.sports_team.championships ?x .
?x ns:sports.sports_championship_event.champion ?c .
?x ns:time.event.end_date ?sk0 .
}
ORDER BY DESC(xsd:datetime(?sk0))
LIMIT 1