PS: I've absolutely no idea why I typed '112' above, which I've only just noticed. I obviously meant '911'! (112 is the Europe-wide equivalent of 999 but it's clearly not relevant here)
A suppose the song Lady is A Tramp first appeared in 1937 in a musical (not by Sinatra) so the song was 'introduced' in 1937.
The clues wording is very clumsy though