Sorry, GUEST,Sam A. Robrin. I've never heard or read that civil rights chant before finding it here. I'd also love to know more about it. As I'm sure you're aware, the "Wallace" mentioned in that chant is the then arch segregationist Alabama govern George Wallace.

The phrase "jump back baby jump back" probably was lifted from Rufus Thomas's hit 1964 R&B song "Jump Back". I don't know why I'm suprised, but a video of his performance of that song is on YouTube. Here's that link:
http://www.youtube.com/watch?v=GPqcccmiOMc

Hat tip to GUEST,Clive Pownceby who posted information about that song in this threads on 22 Mar 11 - 02:52 AM.

Both Rufus Thomas' "Jump Back" and the civil rights chant that Pete Seeger referenced probably owe the "jump back baby jump back" phrase to the "jump back honey jump back" phrase in Paul Laurence Dunbar's poem "A Negro Love Song" (published in 1895). The words to that poem are located on an number of sites, including my newest blog post http://pancocojams.blogspot.com/2011/09/paul-laurence-dunbars-negro-love-song.html

I reposted your comment GUEST,Sam A. Robrin in that blog post with that hope that there might be some response from those readers. If so, I'll add it here.

Thanks and best wishes,

Azizi Powell