How can I create this formula for a custom column in OTBI?

Summary:

I'm attempting to create an asset replacement report with the ability to drill back to the replaced asset (DFF). I need to create a formula to compare two columns, then derive the joined value from a third column.

Content (please ensure you mask any confidential information):

As stated I am attempting to populate a column with the value of a different column on a different row. An example table looks like below:

Assume Column A and Column B are all distinct values, all columns are from the same subject area, and Column C is the DFF using values from Column B.