The function fields() returns the value of the column at the specified offset. The offset is always an integer number, beginning at 1. If the offset is negative, or greater than the number of columns obtained through fieldCount(), the value returned is identical to false ===. If no offset is provided, the value of the first column is returned.

/*
 * DB Connection assumed
 */
$result = $db->execute("SELECT * FROM ACT");
$r = $result->fetchRow();
print $r->fields(1);
/*
 * Returns: 10
 */