To create a lookup single row column in Clay:
1. Use the "Lookup Single Row in Other Table" action.
2. Select the table you want to search in.
3. Choose the target column for your search.
4. Set the filter operator (e.g., equals, contains).
5. Specify the row value to look up.
This action is faster than multiple row lookups and is ideal for searching unique identifiers. If you encounter any issues while setting this up, please let me know the specific problem you're facing, and I'll be happy to help further.