This is their most recent ongoing head-to-head: https://www.chess.com/events/2021-tcec-20-superfinal
Current result: 9 draws, one win with Stockfish as White, and one win with Leela as White. Drawn.
There is also this one from a couple of years ago: https://www.chess.com/news/view/computer-chess-championship-... “Lc0 defeated Stockfish in their head-to-head match, four wins to three”. Stockfish did got more wins against the other computers, so won the round-robin, but in head-to-head games Leela was ahead of Stockfish.