How to get the row number where its ID is 'n' and rows are ordered by some column?
I imagine you'll probably need a secondary ordering column, as Col1 is not a unique value, however this should get you started.

WITH sampledata AS
(
  SELECT 
    ROW_NUMBER() OVER(ORDER BY Col1) as row_num,
    ID,
    Col0,
    Col1,
    Col2
  FROM Table1
)

SELECT 
  row_num 
FROM sampledata 
WHERE ID = 263;