How do I select a field/column from the output of `ls -l`?

Try ls -l | awk '{print $7}'.

awk selects columns so it's perfect for this task.

Never parse ls. Use GNU find. Or if portability isn't important, stat(1).

find . -maxdepth 1 -printf '%Td\n'

For reading data other than lists of filenames line-by-line and splitting into fields, see: BashFAQ/001

There are no methods to reliably read a newline-delimited list of filenames that make sense under most circumstances.