CREATE TABLE $rounds_table (
  ID BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
  state ENUM('OPEN', 'CLOSED', 'PUBLISHED', 'COMPLETE') DEFAULT 'OPEN',
  title TEXT NOT NULL,
  created DATETIME DEFAULT '0000-00-00 00:00:00' NOT NULL,
  PRIMARY KEY(ID)
);

function create_round($name) {
    global $wpdb;
    $rounds_table = $wpdb->prefix . "videovote_rounds";
    $result = $wpdb->insert($rounds_table, array( 'title' => $name, 'state' => 'OPEN', 'created' => 'Now()'));
    return $wpdb->insert_id;
}

create_round("test");


result:
mysql> select * from wp_videovote_rounds;
+----+-------+-------+---------------------+
| ID | state | title | created             |
+----+-------+-------+---------------------+
|  1 | OPEN  |       | 0000-00-00 00:00:00 |
|  2 | OPEN  |       | 0000-00-00 00:00:00 |
+----+-------+-------+---------------------+
2 rows in set (0.00 sec)