This will probably speedup query, since SQL-engine typically apply LIMIT as the last action, not all engines are smart enough to eliminate distinct logic if only one record requested. So, Pony should be smarter. But if someone adds SKIP 42 LIMIT 1, Pony should use distinct anyway.
SKIP 42 LIMIT 1
Original discussion: http://doc.ponyorm.com/queries.html#comment-1654734639
Fixes #90: Do not automatically add "distinct" if query.first() used
Fixed, now Pony implicitly adds .without_distinct() before .first()