what is the {end time} for {St. Louis} has {head of government} as {William D. Becker} ?
At what point was William D. Becker  no longer the head of government for St. Louis?
When did William D. Becker stop being head of government for St. Louis?
SELECT ?l WHERE { resource:St._Louis property:head_of_government ?j . ?j property:head_of_government resource:William_D._Becker . ?j property:end_time ?l }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q38022> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P6> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q8007429> .
?statement <http://www.wikidata.org/entity/P582> ?value. 
} 

SELECT ?value WHERE { wd:Q38022 p:P6 ?s . ?s ps:P6 wd:Q8007429 . ?s pq:P582 ?value}