Delete rows in which the cell of a specific column is empty

You could use the following in the Python Console. Select your layer and use something like:

layer = iface.activeLayer()
with edit(layer):
    listOfIds = [feat.id() for feat in layer.getFeatures() if feat['fieldName'] == NULL]
    layer.deleteFeatures(listOfIds)

You could also filter your layer.

Right click on the layer choose Filter and use "2LE" IS NOT NULL. Afterwards you can right click and Save As another vector layer.

You could use a Virtual Layer, to keep the original data set and to create a new one.

If there is no geometry you have to check "No geometry" in the "Create a virtual layer" window.

There are different ways to check for NULL or ``. See also SQLite select where empty? - on Stack Overflow

Example queries. I was curious about and tested them all with success (no errors):

SELECT * FROM your_table WHERE "2LE" IS NOT NULL

>

SELECT * FROM your_table WHERE "2LE" != 'NULL'  #if `NULL` is a string:

>

SELECT * FROM your_table WHERE ifnull("2LE", '') != ''

>

SELECT * FROM your_table WHERE ifnull(length("2LE"), 0) != 0

>

SELECT * FROM your_table WHERE coalesce("2LE", '') != ''

You can Save As (right click) the query (virtual layer) to a new vector file.