Excel function to copy cell value

Hi all,
i have a worksheet (2010) with three columns:
A - Code
B - Code
C- Description

Columns A and B have same values but in different order. I can't modify the order of column A, and column B is in alph. order. The column C contains the description of the column B. I have to insert in a new column (A1) the right description for codes in A column. How can i do it?

As es:

A B C A1

04 01 pen cat
01 02 table pen
02 03 house table
03 04 cat house

Ty

Luca

I have column A, B and C. Column A1 is my requirement.

These columns come from a ERP (SAP)