You can store a 0, but if you're using a database as a counter then you need to be sure to remove the previous Database values as well. Databases store values until they are manually deleted.

Code
INIT SECTION
DB_Counter(1);

KB SECTION

IF
CharacterLeveledUp(_Char)
THEN
DB_Counter(0);

In this code above, it initializes the DB_Counter at 1. When a character levels up, it adds a 0 to the database.

At that point, the database would look like this-
Code
DB_Counter(1)
DB_Counter(0)


If you really want to reset a database, you could do something like this:
Code
PROC
ProcResetCounter()
AND
DB_Counter(_int)
THEN
NOT DB_Counter(_int)
ProcResetCounter()