List the name of the soccer clubs whose chairman is Joan Laporta.
SELECT DISTINCT ?uri WHERE { ?x <http://dbpedia.org/ontology/chairman> <http://dbpedia.org/resource/Joan_Laporta> . ?x <http://dbpedia.org/property/name> ?uri  . ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/SoccerClub>}
Joan_Laporta