PREFIX po: <http://purl.org/ontology/po/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>

ASK WHERE {
  ?s po:role <http://example.org/profiles/director.html> .

  <http://example.org/profiles/director.html> a po:Role;
     rdfs:label "Director" .
}
