Extracting numbers with a decimal point from ls output in Bash

I would like to extract the numeric part of the file names that begin with "hsli" and end with ".h5" in Bash on Ubuntu 14.04.1 64-bit LTS. My ls -l hsli* output is as follows:

-rwxrwxrwx 1 ongun ongun 31392 Feb 26 13:04 hsli0.03.h5
-rwxrwxrwx 1 ongun ongun 31392 Feb 26 13:44 hsli0.042.h5
-rwxrwxrwx 1 ongun ongun 31392 Feb 26 14:24 hsli0.054.h5
-rwxrwxrwx 1 ongun ongun 31392 Feb 26 15:03 hsli0.066.h5
-rwxrwxrwx 1 ongun ongun 31392 Feb 26 15:42 hsli0.078.h5
-rwxrwxrwx 1 ongun ongun 31392 Feb 26 16:22 hsli0.09.h5
-rwxrwxrwx 1 ongun ongun 31392 Feb 26 17:02 hsli0.102.h5
-rwxrwxrwx 1 ongun ongun 31392 Feb 26 17:36 hsli0.114.h5
-rwxrwxrwx 1 ongun ongun 31392 Feb 26 17:58 hsli0.126.h5
-rwxrwxrwx 1 ongun ongun 31392 Feb 26 18:20 hsli0.138.h5
-rwxrwxrwx 1 ongun ongun 31392 Feb 26 18:42 hsli0.15.h5

They are already in ascending order and after a bit of manipulation I am able to get the file name for the first file with the following command. The command and the output follow below:

$ ls -l hsli* | head -1 | rev | cut -f 1 -d " " | rev 
hsli0.03.h5

Now my aim is to extract 0.03 from here, how can I do so? I am not familiar with regular expressions and this seems like a hard case since there are 2 dots in the file name.