Did {Lyndon_B._Johnson} {spouse} {Lyndon B. Johnson}?
Is it true that Lyndon B. Johnson wed Lyndon B. Johnson?
Did Lyndon B. Johnson marry Lyndon B. Johnson?
ASK WHERE { resource:Lyndon_B._Johnson property:spouse resource:Lyndon_B._Johnson }
 ASK { ?statement1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q9640> . ?statement1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P26> . ?statement1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q9640>. } 
ASK WHERE { wd:Q9640 wdt:P26 wd:Q9640 }