If you have the data in an exported text file (CSV), you can use something like this:
[demo] Search for Number and Return Adjacent Cell in CSV File.kmmacros (3.8 KB)
This works with the CSV file exported from my little sample table in Numbers above.
(Untitled.csv.zip (918 Bytes) )
PS:
Of course, you can also export the table as a tab-delimited text file (TSV). The only change you have to make then is adapting the delimiter in the script.
Here a tab-delimited export: Untitled.tsv.zip (919 Bytes)