In the episode 6x10 of GOT, Littlefinger speaks with Sansa
after they defeated the Boltons
He talks about his dream and they talk about who should lead the North. There Littlefinger has a line:
A trueborn daughter of Ned and Catelyn Stark born here at Winterfell or a motherless bastard born in the south?
Who does he speak of? In the context he could only mean Jon, because it's either him or Sansa who takes command.
But he talks about a motherless bastard from the south. Could Littlefinger know that Jon is the son of Rhaegar or did he only mean that he was born in the south, assuming that he is the child of Ned and that motherless means that no one knows who Jon's mother is?
Am I just over-interpreting things here, or does he speak of someone completely different?