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