Notre Dame.
VB
correct, they won the TAFA Shield (league champions)
They also won the Gooden-Chisholm Cup by beating the southern champion, UBOT, 1-0
Casuals won the TAFA Cup (FA Trophy) by beating Notre Dame in the final, 2-0
Shamrock won the BDV Cup over the Police 1-0.
QRC won the Cow and Gate Cup (intercol)
a more complete overview of the 1939 season end:
http://www.ttfootballhistory.com/node/1413