Question: Which individuals were 2013 Virginia senators who held this government post since 2006-01-14?
Answer(s):
answer: Mark Warner
answer: Jim Webb
answer: Tim Kaine

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.07z1m)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.07z1m ns:government.political_district.representatives ?y .
?y ns:government.government_position_held.office_holder ?x .
?y ns:government.government_position_held.governmental_body ns:m.07t58 .
FILTER(NOT EXISTS {?y ns:government.government_position_held.from ?sk0} || 
EXISTS {?y ns:government.government_position_held.from ?sk1 . 
FILTER(xsd:datetime(?sk1) <= "2013-12-31"^^xsd:dateTime) })
FILTER(NOT EXISTS {?y ns:government.government_position_held.to ?sk2} || 
EXISTS {?y ns:government.government_position_held.to ?sk3 . 
FILTER(xsd:datetime(?sk3) >= "2013-01-01"^^xsd:dateTime) })
?x ns:government.politician.government_positions_held ?c .
?c ns:government.government_position_held.from ?num .
FILTER (?num > "2006-01-14"^^xsd:dateTime) . 
}