If else condition using BI Publisher RTF

I have a report to create requested by the user, now my problem is I was stuck while creating it in an RTF template. Because I have a two columns that contains different value. For example, I have a table that contains a value. Please see below.

<span class="pln" style="font-style: inherit; font-weight: inherit; font-family: inherit; color: #303336;">Item_Number     Discount      Number1       Number2 <br/>Item1           500           145           156</span>

Then I want in the report that when the discount is greater than 0, it will returned the column Number1else Number2

I tried <?xdofx:if DISCOUNT < 0 then ‘Number1’ else 'Number2' end if?>

but I returned the value of the 3 columns. I tried also to removed the apostrophe but I returned the same value.