Although the starting number of 10 may be obvious, you can still define a constant in case you want to use a different one:

  START_NUM   EQU   '10'

I'm not too familiar with interrupts, but I assume you're either practicing with them or are coding this in 16-bit assembly. In either case, you should probably make this clear in the comments, so that the reader knows why you're using an ASCII value instead of a decimal. As you may already know, it's especially important to have plenty of comments in assembly code.

Regarding comments, there can still be obvious ones:

sub eax, 1 ; subract 1

In any context, it's clear that this subtracts 1 from EAX. You may, however, comment on why this is needed, in case it's not obvious.

(and be sure to fix typos in comments)

The output doesn't look too nice with everything close together. It would be better to have a line break after each count, but I don't know the best code for that. If you cannot figure something out, then you can just add a space between each count, with everything still on the same line.

Although the starting number of 10 may be obvious, you can still define a constant in case you want to use a different one:

  START_NUM   EQU   '10'

As you may already know, it's important to have plenty of comments in assembly code.

But, there can still be obvious ones:

sub eax, 1 ; subract 1

In any context, it's clear that this subtracts 1 from EAX. You may, however, comment on why this is needed, in case it's not obvious.

(and be sure to fix typos in comments)

The output doesn't look too nice with everything close together. It would be better to have a line break after each count, but I don't know the best code for that. If you cannot figure something out, then you can just add a space between each count, with everything still on the same line.