Question: Who was the 16th president of the United States?
SPARQL query:
PREFIX onto: <http://dbpedia.org/ontology/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
SELECT DISTINCT ?uri
WHERE {
         ?uri onto:office 'President of the United States' .
         ?uri onto:orderInOffice '16th' .
}