Do something like this to get the least recent date of birth.

SELECT name, datediff(yy, dateofbirth, getdate()) as age, dateofbirth
  FROM tbl
 WHERE gender = 'm'
 ORDER BY dateofbirth
 LIMIT 1

If you use Microsoft SQL Server, you do this.

SELECT TOP (1)
       name, datediff(yy, dateofbirth, getdate()) as age, dateofbirth
  FROM tbl
 WHERE gender = 'm'
 ORDER BY dateofbirth

If we assume everyone in the table is still alive, then the oldest male has the MIN(DOB) . You did not specify any date of death so there you go.

Then you only need to calculate their age.

Something along the lines of:

WITH CTE AS (
SELECT MIN(DOB) AS [minDOB]
FROM table
WHERE gender = 'male'
) --CTE
SELECT *
      ,[Age] = floor((datediff(day,0,@today) - datediff(day,0,@birthdate)) / 365.2425) 
  FROM table
 WHERE DOB = (SELECT [minDOB] FROM CTE) AND gender = 'male'

For the age algorithm I used brianary's answer on a different stackoverflow thread at How to calculate age (in years) based on Date of Birth and getDate()

Feel free to upvote his answer.