Use Column name in order by
SELECT * FROM
(
SELECT empbirth.*, ROW_NUMBER() OVER (order by name) AS RowNum from empbirth
) sortly
WHERE RowNum =8
but if you do'nt want to use col name then you can try as
SELECT * FROM
(
SELECT empbirth.*, ROW_NUMBER() OVER (order by (select top 1 column_name from information_schema.columns
where table_name = 'empbirth')) AS RowNum from empbirth
) sortly
WHERE RowNum =8
Hope it solves your problem