"Do or Do Not" is a humorous story that can be found in Star Wars Tales 15. It's also part of Star Wars Tales Volume 4 and Star Wars Legends Epic Collection: The New Republic Vol. 1.
A few days have passed since the Battle of Endor. We find Luke Skywalker on Endor, wondering aloud why Obi-Wan Kenobi and Yoda haven't appeared to him again. Leia and Han happen to be walking nearby and hear him shouting into the empty air. Leia then decides to have a conversation with him.
Luke admits he's uncertain about his role now. He explains that he has recently discovered he is the last Jedi and that Leia is his sister. He also doesn't know how the Rebel Alliance will reconstruct the galaxy. He then says he feels isolated. Leia reassures him that he will always have the support of his friends and family, and Luke concurs. In a lighthearted manner, he proposes that in the future, she and Han might have Jedi children for him to train. When Leia responds with a doubtful "maybe," the ghost of Yoda materializes and gives Luke a knowing wink.