Single-column record with empty string parsed incorrectly

[kc41]

For request SELECT str_field FROM some_table rows with empty str_field will be parsed not correctly in cause of next:

aiochclient/aiochclient/records.py

Line 35 in c860084

if not self._row:

We will get an empty record instead of record with empty string.
Fix looks like to be trivial. What do you think about removing this if? Could it affects any other cases?

[maximdanilchenko]

This if was added for correct work with with totals queries also (and for empty rows, yes, in this case it is a bug) (https://clickhouse.yandex/docs/en/interfaces/formats/#tabseparated). So we can't just remove it.
We should find the way to handle both cases 🤔

[Maksim-Burtsev]

PR #103 fix it