Question: What is the aldehyde with the highest median lethal dose?
Paraphrase: What aldehyde has the highest lethal dose?
SPARQL (Wikidata): select ?ent where { ?ent wdt:P31 wd:Q101497 . ?ent wdt:P2240 ?obj } ORDER BY DESC(?obj)LIMIT 5 
Answer: acetaldehyde, acetaldehyde, acetaldehyde, acetaldehyde, acetaldehyde