what is the {start time} for {Benito Juárez} has {position held} as {President of Mexico} ?
Benito Juarez was elected to the Presidency of Mexico in what year?
When was Benito Juárez elected as President of Mexico?
SELECT ?x WHERE { resource:Benito_Juárez property:position_held ?w . ?w property:position_held resource:President_of_Mexico . ?w property:start_time ?x }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q182276> .
?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/Q628004> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q182276 p:P39 ?s . ?s ps:P39 wd:Q628004 . ?s pq:P580 ?value}