If quoted string is the only thing you need to handle extra (i.e. no escaped quotes, newlines, etc) and if you have GNU awk:
$ echo '"foo","bar,baz"' | awk -v FPAT='"[^"]*"|[^,]*' '{print $1}'
"foo"
$ echo '"foo","bar,baz"' | awk -v FPAT='"[^"]*"|[^,]*' '{print $2}'
"bar,baz"
For a more robust solution, see https://stackoverflow.com/q/45420535 or use other tools like https://github.com/BurntSushi/xsv