How to mount an ext3 partition from an external sd card on android

I'm trying to run Debian on the Android 4.4 that's installed on my nexus 10 as it is explained in this tutorial :

http://ift.tt/1iiwWx8

I've attached the Leef microSD microUSB Connector to the mini usb port of my nexus 10 as you can see here :

I've created two partitions on the sd card,as explained on the tutorial. The first is formatted with fat fs and the second one with ext3 file system. This is what I did when I've prepared the sd card partitions on the desktop computer :

Disk /dev/sdf: 64.0 GB, 64021856256 bytes
255 heads, 63 sectors/track, 7783 cylinders, total 125042688 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0004504c

   Device Boot      Start         End      Blocks   Id  System
/dev/sdf1            2048    32767999    16382976    b  W95 FAT32
/dev/sdf2        32768000   125042687    46137344   83  Linux

When I attach the leef connector,only the fat32 partition is recognized by android,but not the ext3. This is the mount points that I see :

To proceed with the tutorial I need to mount the second partition where should be installed the debian OS. How can I do this ? thanks.