What is ODS?
LibreOffice and OpenOffice's spreadsheet, and the ISO-standard one - the same ODF packaging an ODT uses, with sheets where a document has pages. Every cell stores its value and, separately, the text shown for it, which is why a figure formatted as currency can still be read back as the number underneath.
What is CSV?
The least glamorous and most durable data format there is: rows of values separated by commas, readable by every spreadsheet and database ever written. All its subtlety is in quoting - a value with a comma in it has to be wrapped in quotes, and a quote inside that has to be doubled.