Clue: 20 down, 19 and 12 across in Dutch village once (6)
Answer: HARLEM
Explanation: Definition: Dutch village once
An anagram ('19 and 12 across' – Brahms and Liszt is rhyming slang for pissed, drunk) of MAHLER ('20 down'). The Dutch city of Haarlem was a village once, and here appears in the English variant, which was adopted by the New York district.