Complex sentence: The team with the most Waratah Bowl championships is the Sydney University Lions, who have won 18 in total and are the current Waratah Bowl champions, having defeated the West Sydney Pirates 20--19 in the 2016 Waratah Bowl.
Split into simpler sentences: The team with the most Waratah Bowl championships is the Sydney University Lions with 18. The current Waratah Bowl champions are the Sydney University Lions, who defeated the West Sydney Pirates 20--19 in the 2016 Waratah Bowl.