First, the query for Max:
SELECT * FROM TAB1 a
WHERE &N = (SELECT count(DISTINCT(b.col1))
FROM TAB1 b WHERE a.col1<=b.col1)
Next, the query for Min:
SELECT * FROM TAB1 a
WHERE &N = (SELECT count(DISTINCT(b.col1))
FROM TAB1 b WHERE a.col1>=b.col1)
If N=1 will return first max or first min. N=2 will return second max or min.