My preferred method is to create a parameter with the substitutions in the form of a HashMap, when you have a large group of substations or if they can change.
You can either pass the substitutions at runtime or set a default value. The benefit being that you can update the map without recompiling your report.
For example if you were to have a parameter named "risk_types" (Using the default language as groovy) you'd set the parameter default value to something like
[1: "HIGH RISK", 2: "LOW RISK"]
In your code, you'd have your text field expression as (where risk_type is the lookup field from the database):
$P{risk_types}.get($F{risk_type})
For items missing in the map, you'd get a null value, I extend the text field expression to be:
$P{risk_types}.get($F{risk_type}) ?: "UNDEFINED"
