sql for row where value=''

This is probably a stupid question but I don't get it.
I have a table called sites

2 rows have a name='siteisdown'
1 row has a value of 1 and the other has a value of '' (nothing)

This works fine, it returns 1 row with a value of 1, along with all the other columns.
"SELECT * from sites where name='siteisdown' AND value =".TRUE);

This returns nothing:
"SELECT * from sites where name='siteisdown' AND value ='' ";

I don't understand why this returns nothing.
How do I call the siteisdown row with a value of nothing ?
.