Leta

Leta is the name of a Little Sister.

Burial at Sea - Episode 2
Elizabeth finds Leta and another Little Sister: Masha Lutz at Dr. Suchong's Free Clinic next to a Dying Big Daddy. Elizabeth needs to get the Big Daddy to move to get past it and the only way to do so is the bring it back with ADAM. Leta drains some ADAM from Masha and gives it to the Big Daddy so it recovers and Elizabeth can move on.

Leta happened to be the Little Sister that provoked Suchong to hit her and caused the Big Daddy to kill him.