List the first drivers of Grand Prixes where Mika Hakkinen was a pole driver.
SELECT DISTINCT ?uri WHERE { ?x <http://dbpedia.org/ontology/poleDriver> <http://dbpedia.org/resource/Mika_Häkkinen> . ?x <http://dbpedia.org/ontology/firstDriver> ?uri  . ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/GrandPrix>}
Mika_Häkkinen