what is the {start time} for {William Howard Taft} has {position held} as {President of the United States} ?
When was William Howard Taft elected as President of the United States?
In what year did William Howard Taft become President of the USA?
SELECT ?q WHERE { ?n property:start_time ?q . resource:William_Howard_Taft property:position_held ?n . ?n property:position_held resource:President_of_the_United_States }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q35648> .
?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/Q11696> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q35648 p:P39 ?s . ?s ps:P39 wd:Q11696 . ?s pq:P580 ?value}