s3object query returns no result for empty field where clause

Question

I'm trying run a query with blank field where clause but it returns no result but with any values same query works fine

Query working fine :

SELECT s3o.Id,s3o.Name,s3o.City FROM s3object s3o WHERE s3o.City = 'Toronto'

But when I try to get result for blank then it returns nothing

SELECT s3o.Id,s3o.Name,s3o.City FROM s3object s3o WHERE s3o.City = ''

I didn't find any documentation in case if there's any other way to get result for blank fields, I tried with IS NULL as well but not working as expected

Is anyone know if there's any other way to achieve it