Question: What is the incumbent of the Al Gore presidential campaign, 2000 and also the president of the Ann Lewis ?
SPARQL query:
PREFIX onto: <http://dbpedia.org/ontology/>
 SELECT DISTINCT ?uri WHERE { <http://dbpedia.org/resource/Al_Gore_presidential_campaign,_2000> onto:incumbent ?uri. <http://dbpedia.org/resource/Ann_Lewis> onto:president ?uri}