Yes it is possible to return the Description field.
List<Asset> assets = [SELECT Id, Description FROM Asset];
If you are getting no rows returned either:
- there is no data or
- you do not have access to the data that is there, or
- your WHERE clause is filter out the data
If the description field is empty then either:
- there is no data in said field or
- you do not have access to the field which does happen even for system admin on some standard fields.
You are returning Rows but no description field, please check your field level access.
Also sometime people create a custom field named Description with less text size and then you may have another field (real stab in the dark there :) )
Here is data returning for me when I use Dev Console: