rounding

How would I round the result of col1to the nearest 10th? The value of col1
(which is an average) is 0.423 in this case but I'm getting the resulting
value of ".0" rather than .4. If I use 0.00 as the second argument, I get
".00".
SELECT
avg(COALESCE(col1*1.0,0.0)) as col1,
FROM table1
_____
DC GSomething like this?
select cast(round(0.423, 1) as decimal(12,1))
ML