To download a specific version of a project, specify the project name'project name', followed by a dash, then the version name. The -y argument answers "yes" to any and all prompts.
The exact 'project name' for a module, is what is included in the URL of the module on D.O., i.e. everything following the last '/' in the URL. So for the Organic Groups module, that would be og, because its URL is https://www.drupal.org/project/og.
As an example, consider something like this:
drush dl og-7.x-1.3
With this command, you download the "og"Organic groups module (replace it with your "module_name"), and more specifically the 7.x-1.3 version7.x-1.3 version of it (replace it with the "version" you want).
You can also specify a development version of a module, as in this exmple (which would download the current 7.x-2.x-dev version of Organic Groups):
drush dl og-7.x-12.x
For many more details, samples, etc, refer to http://www.drushcommands.com/drush-6x/pm/pm-download and/or http://www.drushcommands.com/drush-7x/pm/pm-download. Or to Installing a specific version of a project with drush.
After you downloaded the specific version, you "enable" the module as per the normal Drupal procedures to do so.
If you want to also enable the module using Drush, then there is no more need to specify the version of the module. To continue the above example, to enable the 7.x-1.3 version of it (after you down;oaded it), use a command like so:
drush en og