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