So you want a weapon that is:
decent length
blunt /pierce
There is one: wooden stick. Other than that, bad news:
0 slot weapons have either one (shorter sword but, still with decent length), or the other (pickaxe, hammer).
If there was one with both attributes (except for the very low damage wooden stick), they would become the best possible option, and it would qualify immediately for 1 slot, instead of 0.
The only one that at a quick look might be fine to be made into 0 slot might be the club, and then the wooden stick would be made useless.