Step 1: Understanding the Concept:
The given compound has a benzene ring with two functional groups: an aldehyde group ($-CHO$) and a hydroxyl group ($-OH$).
Step 2: Detailed Explanation:
According to IUPAC priority rules:
1. The aldehyde group ($-CHO$) has higher priority than the hydroxyl group ($-OH$).
2. Therefore, the parent compound is benzaldehyde.
3. The Carbon atom attached to the $-CHO$ group is numbered 1.
4. The Carbon atom attached to the $-OH$ group gets the next lowest possible number, which is 2.
The $-OH$ group is treated as a substituent called "hydroxy".
The name becomes 2-hydroxybenzaldehyde. (Commonly known as Salicylaldehyde).
Step 3: Final Answer:
The IUPAC name is 2-Hydroxybenzaldehyde.