How Do I Use Constants In Stored Procedures?

I have several instances of "magic number" variables (tinyints). In my
program, I have assigned an enumeration to make the meaning clear, such as:

enum Condition {

Green = 0,
Yellow,
Red
}

In my database, one of the tables contains a "Condition" field (tinyint),
which stores the number 0, 1 or 2. However, in my Stored Procedures I am
having to use magic numbers as follows:

SELECT * From Nodes Where Condition = 1

(to select all nodes with yellow condition)

Obviously, meaning is obfuscated here. I would rather use constants but not
have to re-define them in every stored procedure I use.

I there any way to do this?