What is {head of government} of {Phoenix} that is {start time} is {2004-0-0} ?
Who started heading the government of Phoenix in 2004?
SELECT ?obj WHERE { wd:Q16556 p:P6 ?s . ?s ps:P6 ?obj . ?s pq:P580 ?x filter(contains(YEAR(?x),'2004')) }
select distinct ?obj  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q16556> .
?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> ?obj .
?statement <http://www.wikidata.org/entity/P580> <2004-0-0>
} 

Who became head of the government of Phoenix in 2004?