what is the {start time} for {David Ben-Gurion} has {position held} as {Knesset member} ?
Give the date on which David Ben-Gurion became a Knesset member.
When did David Ben-Gurion become a member of the Knesset?
SELECT ?c WHERE { resource:David_Ben-Gurion property:position_held ?k . ?k property:start_time ?c . ?k property:position_held resource:Knesset_member }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q37610> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P39> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q4047513> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q37610 p:P39 ?s . ?s ps:P39 wd:Q4047513 . ?s pq:P580 ?value}