Where did Jacob Marley sit?

Answer 1

Jacob Marley sat on a chair by the fireplace.

Stave 1: Marley's Ghost:

1. "Can you -- can you sit down?" asked Scrooge, looking doubtfully at him.
2. "I can."
3. "Do it then."
4. Scrooge asked the question, because he didn't know whether a ghost so transparent might find himself in a condition to take a chair; and felt that in the event of its being impossible, it might involve the necessity of an embarrassing explanation. But the ghost sat down on the opposite side of the fireplace, as if he were quite used to it.

Answer 2

Jacob Marley sat in Scrooge's old bedroom, next to his own old seat and opposite Scrooge's chair, when he visited Scrooge as a ghost in "A Christmas Carol" by Charles Dickens.