It's always fun to wake up to this...
League 3
1915-16 White Sox/Cardinals
Up 5-3 in 8th, allow one 1 run 8th and 2 runs in 9th. Lose 6-5
League 6
1949-50 Giants/Braves
Up 8-2 thru 6th, allow 4 runs in 7th and 7 runs in 9th. Lose 13-8
League 8
1971-72 Orioles/Phillies
Up 3-0 going into 9th, allow 3 runs for tie. Take lead in 11th. With two outs, nobody on, give up run. Lose in 12 innings 5-4.
League 10
1991-92 Orioles/Rangers
Up 4-2 going into 9th. Two outs, one on, give up 2 runs. Lose 5-4 in ten innings.
There were five other 1-run games that were were decided by a team scoring 1 run in the 9th inning. I went 2-3 in those.