What is the {human} for {head of government} of {Warsaw}
Who is the Prime serve of Warsaw?
Who is the Prime minister of Warsaw?
SELECT DISTINCT ?e WHERE { ?e rdf:type ontology:human . resource:Warsaw property:head_of_government ?e }
select distinct ?obj where { ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q270> . ?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 . ?obj <http://www.wikidata.org/entity/P31> <http://wikidata.dbpedia.org/resource/Q5> } 
 select distinct ?obj where { wd:Q270 wdt:P6 ?obj . ?obj wdt:P31 wd:Q5 } 
Rafał Trzaskowski