you can also install Ubuntu 12.04, you met the System Requirements, which are
Ubuntu Desktop Edition
700 MHz processor (about Intel Celeron or better)
512 MiB RAM (minimum 64mb though)
5 GB of hard-drive space (or USB stick, memory card or external drive but see LiveCD for an alternative approach)
VGA capable of 1024x768 screen resolution
Either a CD/DVD drive or a USB port for the installer media
i also recommend to use Xubuntu or Lubuntu, because of their small desktops.
This will be only enough to actually install and run Xubuntu/Lubuntu, running actually anything on it will be difficult because of the lack of RAM.
on the Xubuntu Site you can find that:
To install or try Xubuntu within the Desktop/Live CD, you need 256 MB of memory. Installing with the Alternative CD requires only 64 MB. Once installed, it is strongly recommended to have at least 512 MB of memory.
so with 64MB of ram there is no real hope for an usable Operating System, al least no Ubuntu.