Where are jockeys in Dubai World Cup from?
SELECT DISTINCT ?uri WHERE { ?x <http://dbpedia.org/ontology/race> <http://dbpedia.org/resource/Dubai_World_Cup> . ?x <http://dbpedia.org/property/birthPlace> ?uri  . ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/Jockey>}
Dubai_World_Cup