To calculate strings to text or character fields, on the dialog box, the string must use double quotation marks ("string"), or in scripting, the string using double quotation marks must also be encapsulated in single quotation marks ('"string"').
It looks like your features are in a shapefile?
SQL is not supported as an input method for Shapefiles, if you select the green tick a tthe bottom of your expression it should valiate it and warn that SQL is only supported for feature services.
Apologies, I was infering frm the FID field rathe tha OBJECTID, I an this alter on a Shapefile and go error above. I also got an error stating it needed to be a feature service t use SQL.
Why do we think this is a shapefile - did I miss something? I would guess that the input is an Excel table (field is Field 1) - ArcGIS cannot directly edit (i.e. calculate a field) Excel tables.
You could copy the table to a feature class in a geodatabase and then do the calculations you need.