Who was the architect of the stadium currently run by the Pittsburgh Pirates?
SELECT DISTINCT ?uri WHERE { ?x <http://dbpedia.org/property/operator> <http://dbpedia.org/resource/Pittsburgh_Pirates> . ?x <http://dbpedia.org/property/architect> ?uri  . ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/Stadium>}
Pittsburgh_Pirates