I have the exact same issue.
$ lsb_release -d Description: Ubuntu 13.10
$ dpkg-query -W deja-dup duplicity deja-dup 27.3.1-0ubuntu1 duplicity 0.6.21-0ubuntu4.1
Running XFCE.
I have the exact same issue.
$ lsb_release -d
Description: Ubuntu 13.10
$ dpkg-query -W deja-dup duplicity
deja-dup 27.3.1-0ubuntu1
duplicity 0.6.21-0ubuntu4.1
Running XFCE.