What is a topic in The Narrative of the Life of Fredrick Douglass that I can compare and contrast? The topic needs to be in the book only as well.

There are several topics in this classic work which you could compare and contrast.

The two biggest are also fairly obvious. First, you could compare the experience of African Americans and Caucasians during the period of slavery (as shown in this book). Second, you could compare the life Douglass led as a slave to the life he led once he was free. These would address a number of the book's major themes, and you would have a lot of examples to work with.

A more subtle compare and contrast approach would be to compare the different owners or slaveholders Douglass encounters. That way you could look at a very complex issue: how did the attitudes of whites, specifically slave owners, differ from one another? And where do they differ (that's the contrast)? You could then make an argument about what these similarities and differences mean.