Mysql have UNIQUE Name and Tag it shouldn't insert data if aney of those two is same, now it work when both are same.
$sql = "INSERT IGNORE INTO tribe (Name, Tag, Points, PointsTotal, Villages, Rank) VALUES ('$addName', '$addTag', 11, 11, 1, 3)";
$result = mysql_query($sql);/* IF NOT EXISTS, INSERT IGNORE */
if (!mysql_affected_rows()) {
notice ("Tribe name or tag is duplicated. Change it.", 1);
}