What date did Lech Kaczyński die in the 2010 Polish Air Force Tu-154 crash?
SELECT ?obj WHERE { wd:Q2757 p:P570 ?s . ?s ps:P570 ?obj . ?s pq:P805 wd:Q131311 }
lech kaczyński: Q2757 2010 polish air force tu-154 crash: Q131311