How to create text base field without format? How to create base field without format surplus?

E.g. this

$fields['data'] = BaseFieldDefinition::create('text_long')
  -&gt;setLabel(t('XML Data'))
  -&gt;setDescription(t('The product XML data.'));


creates two columns in the table:

`data__value` longtext,
`data__format` varchar(255) CHARACTER SET ascii DEFAULT NULL,
Text (plain, long) field type is string_long.

https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Core%21Field%21Plugin%21Field%21FieldType%21StringLongItem.php/class/StringLongItem/8.2.x